# V8 engine Cessna 172

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#### rv7charlie

##### Well-Known Member
I get the liability concerns, but when I said C210-like, that's what I meant; *like*. I'd never be able to afford an actual Type Certificated C210, nor would I ever want one.

Shucks; sell us an airboat reduction drive, and a highly flexible airboat engine controller. I'm pretty sure no one in the exp-homebuilt or exp-exhibition categories would complain about flying boat parts. I know that a lot of Swift owners fly a boat part to make their gear & flaps go up & down (but there's no paperwork that talks about it...).

#### proppastie

##### Well-Known Member
Log Member
Experimental op limits were re-written years ago that remove most of the restrictive op limitations for the exhibitions category
liability in the US is really an obstacle.
You probably have considered the following options.......Perhaps you sell plans, expensive book? .......you can be assured that it will be the rare case that the plans are followed exactly (homebuilders like to make "improvements"?) and that might get you off the hook liability wise......Other US designs have been sold to foreign concerns to escape US liability.......You might work on a "bullet proof" "idiot proof" simple setup with sealed proprietary electronics and proprietary hardware and you being the only installer of the system so that you can maintain the quality required to reduce your liability.........just supplying the electronics or the prop drive would be a big job for a small organization. There are reasons it is easy to make a small fortune in aviation .....good luck.

#### pfarber

##### Well-Known Member

If people REALLY want a 172, well, build one. Any patents have long expired and as long as you don't call it a Cessna 172 then you are golden. There are enough hulls out there to make plans.

But who wants a 172 when there are much more viable 4 seaters out there that you can buy or build (E/AB).

I cannot understand how people can lust for a 50-60 year old airframe and walk past professional build E/ABs that are a few years old and out perform anything Cessna put out.

#### skydawg

##### Well-Known Member
pffarber
you are by far the most critical poster I've run across. I don't know your experience in the aviation manufacturing industry, but liability for a certified product kills many new and low quantity manufacturers ability to reach market. For an STC version of the V8 manufacturers basic liability insurance would cost us many times any profit margin. A good indication of apples to apples are identical products sold in both EXP & CERT versions, such as the Garmin G5 which cost half that of the experimental version; or EXP vs CERT Lycoming cost.... same engine, far different risk exposure. Experimental has enjoyed few, if any, meaningful product liability losses, and thus curtails risk. I would argue this is why EXP growth far out paces cert market, both directly, and indirectly by more companies offering more advanced products and at far lower cost.

AS far as why not build a C172 from scratch or a kit.... GAMA and other industry info suggest most pilots don't have the time or skills, and many just want to get their pilots cert without such a long build. IN fact, most GA trained airline pilots never fly a GA plane after being hired, and career bound pilots make up a majority of piston GA flight hours flown. As far as why not just by an experimental: there is not enough trainers to meet any fleet demand for fleet operators, and again, most pilots don't want to own a plane for numerous reasons. A few E/AB clubs have tried using fleet for training but insurance remains an obstacle for EXP/AB planes for carriers. There are also few 4 seater E/AB. .... This is why we designed the V8 conversion.... it can be used in a equity based flight club for training and time building and personal use, installed in legacy airframes that are numerous and relatively cheap, and have insurance options at same cost as a cert C172. AS far a intellectual property sunsets, a few companies have knocked off the Cessna designs, but as you pointed out, it was still an antique and failed as one could buy the real thing for much less.

#### proppastie

##### Well-Known Member
Log Member
This is why we designed the V8 conversion.
There are many other certified engines which could be STC and existing stock engines for the 172 or 182......will you be able to compete price wise with a new-limits over hauled engine?

#### Victor Bravo

##### Well-Known Member
HBA Supporter
I cannot understand how people can lust for a 50-60 year old airframe and walk past professional build E/ABs that are a few years old and out perform anything Cessna put out.
Because "performance" is not nearly the whole story for aircraft ownership, enjoyment, or long-term success.

I just flew my 65 year old obsolete antique Cessna, and its obsolete 1930's technology engine today, and was very much moved by the fact that the quality and usefulness and trustworthiness of this old airplane has stood the test of time. It was designed by very highly competent people, with safety, long-term reliability, and ease of flight as a top priority. These comments may be off-topic to discuss on a homebuilt airplanes forum, and the fact that I'm an active participant here should verify that I have an appreciation and interest in E-AB's. Professional race car drivers and builders have an understanding and deep appreciation of the minivan sitting in their driveway at home.

#### Aviacs

##### Well-Known Member
I cannot understand how people can lust for a 50-60 year old airframe
Piling on various aspects of the discussion, and to hammer some more on my earlier point that Cessna actually did make a superior "172" version that more or less maxed out the performance envelop of the airframe*.....but the market yawned.....

If my retirement income supported it, i'd be right back in a C175 with millenium cylinders, maybe TW conversion, and fly happily into the sunset.

Instead, i fly club C140 (with millenium cylinders ), pre-war J3, and was just approved last month for hangar space at the end of this month for Sonerai2 rebuild project.

*with all due respect to various mentions of alternate engines and supposed "upgrades", the GO-300 is nearly perfect for the airframe as designed and offers the best useful load compared to alternatives. At the point at which the airframe performs in the top of the green or into the low end of the yellow, what does adding more HP & weight gain? If better initial Vx is necessary for "difficult" regimes, use the constant speed prop version. I believe the straight prop was faster at altitude, though. But Cessna never sold enough to work out the cylinder head problems that were endemic across the 0-200/0-300 line & exacerbated in the GO.

#### Pops

##### Well-Known Member
HBA Supporter
Log Member
My daughter used to own a 1963 ( wished it was a 1964 with the center stack radios) Cessna 172 with the Lyc-360 conversion with the fixed pitch prop. STC had the battery moved to the rear of the baggage compartment, had 100 lbs GW increase STC. Great IFR panel with everything coupled to the autopilot.
The only down side was the shorter range without the long range fuel tanks. ( needed 175 wings).
Old friend of mine had the same in a 1966 Cessna 172 ( different STC) but with the constant speed prop and battery on the firewall and the wing STOL kit. He said he wished he had went to the Bush STC conversion that the 1963 had. His 1966 was nose heavy and in performance could get off the ground in just a few feet quicker and climb maybe 100 feet ROC better. But , no faster.
I flew the 1963 to Cleveland, Ohio and back to pickup a friend and had an average ground speed of 151 mph for the round trip.
Just about the perfect C-172 except for not having the center stack radio panel and more range. I liked it better than the same year C-182.

I would like to have a 1959 straight tail C-172 with the Lyc 180 conversion with the fixed pitch prop and the C-175 wings for the longer range. Light weight as possible, with no paint , (polished ) except for the paint trim colors. Basically my old 1959 C-172 with adding the Lyc 180 Hp conversion. Picture.

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#### BJC

##### Well-Known Member
HBA Supporter
With each “improvement” that Cessna added to the C172 - swept tail, omni vision, fancy interiors, heavy wheel farings, etc., - the performance suffered.

My neighbor has a straight tail C172, converted to tailwheel, with a Lycoming O-360 and a CS prop. Would probably preform better with a FP prop, but it is a nice airplane.

BJC

#### Pops

##### Well-Known Member
HBA Supporter
Log Member
With each “improvement” that Cessna added to the C172 - swept tail, omni vision, fancy interiors, heavy wheel farings, etc., - the performance suffered.

My neighbor has a straight tail C172, converted to tailwheel, with a Lycoming O-360 and a CS prop. Would probably preform better with a FP prop, but it is a nice airplane.

BJC
Your are correct. I also had a 1956 C-172 built in Nov 1955. 272th one built. After several years I sold it to the buyer in D.C. Buyer rented a new 172 and flew in with another pilot to get my 56. After getting home, he called me and said that my 56 handled far better than the new 172 , out climbed, was faster than the new 172.

#### pfarber

##### Well-Known Member
pffarber
you are by far the most critical poster I've run across. I don't know your experience in the aviation manufacturing industry, but liability for a certified product kills many new and low quantity manufacturers ability to reach market. For an STC version of the V8 manufacturers basic liability insurance would cost us many times any profit margin. A good indication of apples to apples are identical products sold in both EXP & CERT versions, such as the Garmin G5 which cost half that of the experimental version; or EXP vs CERT Lycoming cost.... same engine, far different risk exposure. Experimental has enjoyed few, if any, meaningful product liability losses, and thus curtails risk. I would argue this is why EXP growth far out paces cert market, both directly, and indirectly by more companies offering more advanced products and at far lower cost.

AS far as why not build a C172 from scratch or a kit.... GAMA and other industry info suggest most pilots don't have the time or skills, and many just want to get their pilots cert without such a long build. IN fact, most GA trained airline pilots never fly a GA plane after being hired, and career bound pilots make up a majority of piston GA flight hours flown. As far as why not just by an experimental: there is not enough trainers to meet any fleet demand for fleet operators, and again, most pilots don't want to own a plane for numerous reasons. A few E/AB clubs have tried using fleet for training but insurance remains an obstacle for EXP/AB planes for carriers. There are also few 4 seater E/AB. .... This is why we designed the V8 conversion.... it can be used in a equity based flight club for training and time building and personal use, installed in legacy airframes that are numerous and relatively cheap, and have insurance options at same cost as a cert C172. AS far a intellectual property sunsets, a few companies have knocked off the Cessna designs, but as you pointed out, it was still an antique and failed as one could buy the real thing for much less.
More vague posts of 'it costs more'. Show us. What were your numbers?

As for the G5, there is ZERO parts difference between the two. The only difference in the paperwork. I can sue Garmin if I install a G5 in an E/AB just as easily as I could if its in a certified AC. There is no 'get out of lawsuits' free card just because its in a E/AB. Garmin is a rip off... take a UAV-30. Basically a G5, the certified version - $1900, the E/B version$1500. $400. 20% less? The exact same parts. Where is the big liability cost? Why is Garmin putting a 50% 'liability' on the cost when other's don't? Gamin can, that's why. As for engines, Vans sells an Non-certified o-320-d1a for$31000 and I've found prices listed for NEW certified o-320 -a and -b for only $36,000...$6k? That's it? Where is all this big liability money at? 15% I'm not seeing a huge liability cost.

if you think that being asked to provide some actual numbers is mean or contrary, well, that's on you. I don't want your opinion... I want the facts. Please show me where all this liability money is at?

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#### TFF

Technically if you went to Lycomings front door and asked for a New O-320 it’s is $78,000. Vans gets a manufacturer discount like Cessna because of volume. You buy a new Cessna, you are paying 78k for the engine. That is why good cores hold their value. #### mcrae0104 ##### Well-Known Member HBA Supporter Log Member @pfarber, as HBA’s most experienced and foremost critic, do you have any constructive criticism for this project, or do you just want to #&*# on it? @skydawg, next time I’m on your side of town, the beer’s on me. This is very cool. #### Victor Bravo ##### Well-Known Member HBA Supporter The only difference in the paperwork. The exact same parts. Where is the big liability cost? Why is Garmin putting a 50% 'liability' on the cost when other's don't? Gamin can, that's why. I have an FAA certified product that I manufacture, so I can speak here from experience. The overall answer to your question (if you had asked that question to me about my product) is: "The two years and$25K that it took just to get the finished product certified (after I had designed, tested and set up the manufacture), with all the initial paperwork, plus the money and time it takes to do the paperwork on every one I build from then on."

That's on a $499 retail product with one mechanical moving part, that will not crash an airplane even if every part of it fails at the worst time. Garmin makes a product that people in an airplane are relying on for their life in some circumstances. Their product has hundreds of separate electronic components which can burn out or go bad, and their product probably cost them$500K to get certified.

Garmin's answer also includes something my answer does not, which is "The enormous cost of an insurance policy that covers the level of liability which comes with a flight-critical aircraft instrument".

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#### Pilot-34

##### Well-Known Member
Can build a lot of good planes out of a 175, I think the 3A17 airframe has advantages over the plain 172. Convert it to tailwheel, install the V8 with a long prop. That would make a cool plane.
There was one of those for sale on craigslist near Talkeetna Alaska couple years ago.

It seems like it went pretty cheap to but if I remember right that was about the low point in value for the 175 airframe.

#### skydawg

##### Well-Known Member
initially faa wanted us to use a certified carb and distributor on a modern V8....there was no way unless we heavily modified the block, but.... spoke with carb manufacturer.. Cost of certified carb was more than 3X of experimental version due to liability risk and even then they were not sure they wanted to sell anything if it were to be certified regardless of price.

years ago I designed a simple float switch that mounted on stock fuel sender that would ground a wire to illuminate a low fuel warn lamp. The cert process was doable but could not get any product liability insurance regardless of how simple....to victor bravos point, was told if someone claimed the light failed and someone runs dry, they would blame the light. It becomes a critical component and no small company could afford the risk. Too bad actually, it worked well and many are still running dry.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
Quote: "Although Corsair is seeking FAA STC certification as a replacement engine for certified airframes, initial focus will be foreign customers for STC conversion kits- due to domestic liability issues of certified aircraft. Kits for certified aircraft types may be available to domestic operators within the ‘restricted’ or ‘POA’ airworthiness categories, or converting to the experimental category."

I don't think any STC for an engine is possible. It would be a Type certificate. And with all the quality control paperwork of each part. Who has done any STC for a complete engine in the US? (the STC is for the kit for installing a Type certificated conversion engine)

#### Victor Bravo

##### Well-Known Member
HBA Supporter
I was told by Jim Rust of Whirlwind Propellers that I could not ever STC or even "one-time certify" one of his EXP propellers on my 172. Not because it wouldn't pass the testing for a one-shot STC (his props would definitely pass), but because the FAA requires any propeller to undergo its own certification as an aircraft propeller... THEN you can apply for an STC to install that certified propeller on some airplane that it wasn't originally TC'd on.

I have to believe they used the same logic for engines. I would guess that by specific rule you cannot get an STC to put an uncertified engine on a standard category airplane. However, I'd also bet that you have at least some chance of getting an STC to put something like this in a restricted category airplane (crop sprayer, banner tow, sky-writer, etc.).

I would also think that they would allow the engine to be installed on a certified airframe under "Flight Test", if you were gathering data and test results toward an eventual type certificate for the engine.

I'm also guessing skydawg has already found all of this out long before now.

#### rv6ejguy

##### Well-Known Member
The other part that will make this all too expensive for certification is that you'd be required to show traceability of all engine components as passing process control and quality control during manufacture unless the FAA will waive that requirement and allow you to use a less stringent ASTM cert as LSA regs allow I believe. Using 3rd party parts here (GM manufactured) probably won't fly with the FAA without a lot of NDT and QC checks to verify part quality and compliance. The certified paper trail required will up the cost substantially.

Even getting individual components PMA'd is a lengthy and expensive process.

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#### TFF

##### Well-Known Member
There is no magic in the system to get this stuff through, which is what everyone is looking for. It was designed for companies not hobbyists. The few oddball stuff STCed, over the years when a local office would sign, is over dead and gone. The Grumman AA-1 320 engine STCs are based upon you only using 108 hp of the 320s 150-160 hp; now don’t go over that arbitrary redline Mr Pilot. That only got past because logic was applied that is not valid anymore. Rare then. It’s only about rule following now.
If you don’t have an engineering department and a large liability insurance policy, you are not getting a new one passed. You have to be able to handle ADs that the FAA wants you to engineer for them and you have to compensate the legal system that will sue you. If you can’t engineer AD fixes, that leaves it up the the government to decide anything they want. No insurance, how will lawyers make a living? That is what happened to the Aeromatic prop guy. They deemed his shop too small and without enough assets to handle a disaster. Bullied him into giving up his STC paperwork.

That is why the homebuilt community has grown. For all who wants a certified airplane homebuilt; stop complaining. It’s not going to happen. In fact the doors are trying to close on all of it, so wasting time complaining just means you won’t have any fun. Get to work either building or making money to buy.